The present invention relates to a steering apparatus for a boat, and more particularly, to a steering apparatus for a small boat and the like, in which a steering mechanism can be operated remotely by means of push-pull control cable for transmission of steering force, and steering position adjustment work and assembly/disassembly work of which are easy to perform.
Hitherto, as a steering apparatus for a boat, there was used a steering apparatus using push-pull control cable for transmission of steering force because of its superior remote-operability and space saving effect in a boat.
Fundamental construction of the above-mentioned steering apparatus for a boat is explained hereinafter with reference to FIG. 7.
In FIG. 7, numeral 1 means a steering wheel mounted at an operator's seat of a boat, 2 means a push-pull control cable, 3 means a steering mechanism and 4 means a rudder. The rudder can be substituted by an outboard motor being rotatably mounted on the hull or stern of the boat, of which outline is illustrated by imaginary lines in FIG. 5. In the present specification, a word "rudder means" or "rudder" has a broad concept including such an outboard motor. In the steering apparatus for a boat of FIG. 7, when the steering wheel 1 is rotated, an inner cable of the push-pull control cable 2 is pulled or pushed, then a steering rod 5 in the steering mechanism 3 is moved in the direction shown by arrow a or b. Consequently, the rudder 4 is operated via a steering link 6 connected to the steering rod 5. Although not shown in FIG. 7, one end of the inner cable of the push-pull control cable 2 is connected to a rack-pinion mechanism 7 which is driven by the steering wheel 1, and the other end is connected to the above-mentioned steering rod 5 slidably guided by a guide pipe 8 which is provided in the steering mechanism 3.
In a conventional steering apparatus for a boat, the later end of a conduit of the push-pull control cable 2 is connected to the steering mechanism 3 by connecting a cable cap fixed on the end of the conduit with an end of the guide pipe 8 using a semi-box nut 9, i.e. a nut having an annular bottom.
However, the conventional steering apparatus for a boat described above have the following problems:
(1) The push-pull control cable 2 and the steering rod 5 are manufactured so as to have certain prespecified lengths, then installed on a boat at outfitting stage together with the steering wheel 1 and steering mechanism 3. However, the rack-pinion mechanism 7 on the side of the steering wheel 1 and the steering mechanism 3 are usually associated with manufacturing errors and installation errors. As a result of that, in a completed apparatus, there exists a problem that the straight-forward position of the steering wheel 1 does not make the rudder 4 in the straightforward position to cause some error. Without solving this problem, there is caused an inconvenience in navigating a boat that an operator cannot navigate a boat straightforward with relying on the straightforward position of the steering wheel 1 (e.g. the position in which the spoke 1a is in an upright posture).
(2) In a small boat having limited space availability, sometime the rack-pinion mechanism 7 is installed in an inclined posture, i.e. being rotated in a small angle around the axis of the steering wheel 1. In that case, the angle differs a little depending on the size of the boat.
Consequently, many kinds of push-pull control cables 2 having different length are required when the apparatus is applied to a series of different kinds of boats. However, to provide many kinds of push-pull control cables 2 makes the cost increase, then it is undesirable.
(3) A boat has a behavior or tendency of turning right or left a little during the navigation caused by the effect of turning torque of the thruster. Each boat has an individual behavior described above, and that differs a little. However, the correction of the straightforward position of the rudder to compensate above behavior cannot be achieved in the conventional steering apparatus but only the skill of the operator can compensate the behavior.
An object of the present invention is to provide a steering apparatus for a boat in which to adjust the straightforward positions of the steering wheel and the rudder is easy when they are installed in the boat, to apply to different kinds of boats is easy, to compensate a behavior of an individual boat is previously enabled and to assemble and disassemble thereof are easy.